ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris)

[GuateGojira]

That is also a good explanation. After all, is impossible to avoid the fact that in modern times, Amur tigers and China tigers probably crossed they pats in the south of the Manchurian region.

In fact, there is some discrepancy between Mazák (1983) and Nowell & Jackson (1996) about the classification of the specimens in Central China. This map from Kitchener & Dugmore (1999) show the problem.

*This image is copyright of its original author

Interesting, don't you think? Proportions of the tiger:
Some time ago, I worked in a series of measurements on live tigers in order to get an accurate idea of the proportions of the body of a tiger. In this case, I was trying to found how much of the length of a tiger correspond to the head. My final results produced a ratio of 5.46, which means that the greatest skull length will correspond to this number. I have found a few more measurements now, but for the moment, I would like to share with all of you my first experiments. The original publication was in KingT forum (http://animalbattle.yuku.com/topic/21/bo...1X6N1cXK8w). I will put my new data latter. Enjoy the reading.
 



 

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1. Proportions of the tiger – head length:
Check this image of Baikal:
[img]http://imageshack.com/scaled/large/838/a958.png" class="lozad max-img-size" alt="" title="">

*This image is copyright of its original author

 
As we can see, the head-body length of this tiger is about 5 times its head length. Take in count that the body of Bailkal is crouched, so if it were stretched, they will match perfectly with the five bars on its back.
 
This suggests that Mazák assumption that the large Amur tigers had heads that represents about 1/5 of the head-body seems to be correct. Now, let’s see if this value is accurate.
 
Now, check the proportions of “head-body – head length” the other captive Amur tigers:
* Amur No. 11: 4.89
* Benjamin No. 102: 4.79
* Amur No. 143: 4.20
Average ratio: 4.63 – range 4.20-4.89
 
This is close to the 1/5 estimated by Mazák. Sadly, these are the only captive specimens that have its head-length available.
 
Now, let’s use the CBL of all the specimens, including those of Dr Christiansen, to achieve the ratio of “head-body – CBL”:
* CN5698: CBL=350.9 mm – HB-CBL= 5.81
* CN5697: CBL=334.2 mm – HB-CBL= 6.16
* CN6049: CBL=337.8 mm – HB-CBL= 5.77
* Amur No. 11: CBL=322.5 mm – HB-CBL= 6.82
* Benjamin No. 102: CBL=331.2 mm – HB-CBL= 6.07
Average ratio: 6.13
 
I consider these measurements more reliable, as are based in the actual bones compared with the body length. Head-length only is very variable and can change depending of the musculature of the face. Body length can change to, but the difference in musculature is less than in the head.
 
Now, the wild ones, to get the “head-body – head length”:
Zheny-1: HL=41 cm – HL-HBL= 4.78
Dale: HL=45 cm – HL-HBL= 4.44
Aleksei: HL=41 cm – HL-HBL= 4.51
Igor: HL=46 cm – HL-HBL= 4.39
Maurice: HL=41 cm – HL-HBL= 5.07
Sasha: HL=48 cm – HL-HBL= 4.13
Misha: HL=46 cm – HL-HBL= 4.17
Valodia: HL=43 cm – HL-HBL= 4.51
Andrey: HL=40 cm – HL-HBL= 4.98
Victor: HL=38 cm – HL-HBL= 5.00
Zheny-2: HL=37 cm – HL-HBL= 4.81
Average ratio: 4.62 – range 4.13-5.07
 
Interesting both captive (4.63) and wild (4.62) specimens have about the same “head-body – head length” proportions. The range of wild specimens is more variable because the sample is larger.
 
This data show that Mazák was correct, as 4.6 is just slightly less than the 1/5 estimated by him. Sadly, we don’t count with this data for the other tiger populations.
 
Taking in count that we estimated an average head-body length (in straight line) of 233 cm, based in the large femur, for the largest Ngandong tiger, we can obtain the head length based in the Amur tiger ratios:
* Wild specimens: ratio 4.62 – head of 504 mm.
* Captive specimens: ratio 4.63 – head of 503 mm.
 
Now using the average ratio of 1.16 like the relation of “head length and GSL”, we can get the following GSL estimations:
* Wild specimens: 504 mm / 1.16 = 434.5 mm.
* Captive specimens: 503 mm / 1.16 = 433.6 mm.
 
The average GSL would be of 434 mm, which is only 6 millimeters less than the previous estimation of 440 mm. This is evidence that tigers are very symmetrical animals and there is no doubt that these same proportions are shared with all the other tiger populations.
 
So, here are the body proportions of the tigers, based in Amur specimens:
 
* Head-body length – head length = 4.62
* Head-body length – Condylobasal length = 6.13
* Head length – greatest skull length = 1.16
 
Obviously these values can be variable depending of the specimens, but at least they are useful to estimate body size of extinct Pleistocene tigers.
 

 

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2. Proportions of the tiger – Sunda tigers:
You will remember the document of Sody (1949) that presents a large database of tiger skulls from Sumatra, Java and Bali. Besides, it presents the body size of 13 specimens, 9 of them associated with its skull.
 
Here is the full list of specimens:

*This image is copyright of its original author

Interesting as it is, the values of the male Sumatran specimens are all lower than those of the Amur tigers, suggesting that this race had a relative larger head in relation to its body. On the other hand, the only Javanese male tiger available match perfectly with the average values of the Amur tiger, suggesting that this “pure” race of Sunda tigers kept the same proportions than the mainland tigers. The Sumatran tigers, been a natural hybrid of mainland and Sunda tigers, probably evolved a different body proportions and completely different cranial characteristics, that have been presented by Mazák & Groves (2006) and Mazák (2008).
 
The values of the females are more confuse as there are not comparison parameters, as with the males. Only one female (Padang, Sumatra) fit well into the ratios of the male specimens, but the other specimens, especially those from Bali, are obviously very inflated and represent specimens measured “over curves” or from skins.
 
As we don’t know the proportions of skull-body for females, it is difficult to get an accurate conclusion, especially in the case of the other two specimens from Sumatra and Java.
 
Conclusion:
We can conclude that Sumatran tigers seem to have larger heads in relation to its body, probably comparable to the African lions (My own data, unpublished). This proportion is shared also with the only female tiger apparently also measured between pegs.
 
The measurements of the two Bali tigresses are definitely not reliable and were taken from skins or over curves. This was clearly stated by Mazák in two documents.
 
As for the Javanese tigers, only the male seems to have been measured between pegs. The female skull, using the ratio of the male and those of the Amur tigers, gives a head-body of c.1470 mm, which is 22 cm less than the presented figure, which suggests that the measurement was taken from a skin.
 
For comparison, three South Chinese tigers, measured between pegs, present the following ratios:
 
Location       GSL                HB                  Ratio
Amoy-1          343                 1850               5.39
Shanxi           346                 1990               5.75
Amoy-2          321.7              1760               5.47
Average ratio is of 5.54
 
It seems that the Javanese tiger (5.44) is slightly less than the average ratio from China, and these last two fit perfectly between the ratios of the Amur race (5.19-5.93).
 
Mainland tigers (Amur and China overall) seems to have a ratio of 5.47 (n=8) between the Greatest Skull Length and the head-body length. For the only Javanese male tiger (5.44) the figure is the about the same and suggests a similar evolutionary pattern that probably arises for the first time in the last (and largest) specimens of the Wanhsien tiger. If we put together the five Amur, 3 South China and 1 Javanese specimens, the ratio of head-body - GSL is of 5.46.


We can conclude, with some degree of certainest, that we can multiply 5.46 (or 5.5 if you want just one decimal, the difference in the result is minimal) to any GSL specimen and we will have a plausible head-body length in straight line.

 

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3. Proportions of the tiger – the new ratio reliability:
Now that we have a ratio of 5.46 for the “Head-body – GSL” for the tiger (Amur, China and Java together), we can prove this value with known specimens.
 
Did you remember the Gondol tiger?

*This image is copyright of its original author

Source: Buzas & Farkas, 1997.
 
This is the largest Balinese tiger on record with a GSL of 312 mm, slightly larger than the largest skull recorded for the Venezuela jaguars of Los Llanos (312.5 mm GSL and 1700 mm in Head-body “between pegs”). The head-body of this large tiger is reported as 1740 mm. If we apply the new ratio, we get:
 
GSL 312 * 5.46 = 1704 mm.
 
As we can see, the result is just slightly smaller (less than 4 cm) than the reported size. Although the hunter (Vojnich) doesn’t report the method of measurement, this data suggest that it was taken in straight line. The total length was of 245 cm, which is slightly longer than the record calculated by Mazák (230 cm). Please take in count that Mazák never knew about this large skull.
 
At the end, the result was slightly lower, but overall it was accurate.
 
Now, let’s prove with other large skulls:
 
* Record Bengal from Mazák – 378 mm = 2064 mm HB.
* Record Amur from Mazák – 383 mm = 2091 mm HB.
* Record Amur from Kitchener – 406 mm = 2217 mm HB.
* Record Bengal from Hewett – 413 = 2255 mm HB.
 
These results match very well with the known maximum sizes for the species. For example, the longest Bengal tiger measured by scientist (HB) was of 204 cm (Karanth, 1993), while the largest Amur was of 208 cm (Kerley et al, 2005). For the old records, the longest Bengal tiger was of 221 cm in HB (Brander, 1923), while the longest Amur tiger reported by Mazák (1981) was of probably about 220 cm in HB (total length of 330 cm).
 
These are only a few examples that shows that the ratio of 5.46 produce reliable results. However, we must take in count that even when tigers are very symmetric animals, there are variations. For example, the longest tiger on record between pegs (322 cm in total length; 213 cm in head-body) had a skull length of 381 mm, which produce a ratio of 5.59. This fits very well with the overall data, but is higher than my new ratio.
 
Like a form of conclusion, I will quote Sterndale (1884):
“I quite expect to be criticized, but if the crude idea can be improved on by others I shall be glad”.
 
I think that his words apply very well to my hypothesis. With more data, this method and ratio will be better in the future. Greetings to all. Reply